In the past, a wide variety of golf swing training devices have been developed. U.S. Pat. No. 4,280,701 illustrates one such device, featuring an open ring mounted to a base which is movable during the golfer's stroke. Such devices are heavy and mechanically complicated, detracting from their utility in that portability of the device is not a feature which is designed in such a device. Similar devices which are mechanically complex in adjustment and construction are shown in U.S. Pat. Nos. 3,795,399; 3,711,103; and 3,489,416. Some of these devices don't use actual clubs at all, such as U.S. Pat. No. 3,794,329. Others require specially modified clubs, such as U.S. Pat. No. 4,583,740. U.S. Pat. No. 3,415,523 employs complex linkages hooked not only to the golfer's club but to a helmet to be worn on the head. Some provide a crescent-shaped guide to hold a carriage to which the club is guided by what amounts to an oarlock or an open-topped U-shaped bracket to assist the golfer in following the track. This type of open-grip design for the club facilitates the club coming out of contact with the carriage and guide assembly. Other devices comprised a freestanding pedestal hooked up to the club connected to a complicated assortment of linkages and such devices is U.S. Pat. No. 3,604,712. counterweights to facilitate control of the golfer's swing. Typical of such devices is U.S. Pat. No. 3,604,712.
Yet another style of these golf swing practice devices are those that have a rod-directed feature. Typical of these are U.S. Pat. Nos. 4,449,708; 4,211,418; 4,580,786; 4,486,020; and 4,653,757. Other types of devices employ a rail but no attachment between the rail and the club. The rail simply serves as a rest for the club throughout the swing. Typical of these devices are U.S. Pat. No. 3,583,707; 3,730,531; and 3,744,799. U.S. Pat. No. 4,071,251 provides a set of parallel tubes between which the golf club can be swung, wherein the parallel tubes act as a guide. U.S. Pat. No. 4,815,743 illustrates a device connected to the golfer s neck and shoulders rather than the club.
Yet other devices employ cords to guide the swing, such as illustrated in U.S. Pat. Nos. 4,034,991 and 3,917,281.
The following patents also relate to golf swing training devices and work on various principles illustrated in the other patents referred to above: U.S. Pat. No. 3,703,294 is a cord-guided device; U.S. Pat. No. 4,023,811 is a series of parallel tracks, useful to delineate the preferred trajectory for a swing; U.S. Pat. No. 4,678,193 is a freestanding frame supporting a curved rod used to train the golfer's swing; U.S. Pat. No. 3,341,208 is a ring on which the club can rest as a guide to the golfer in swinging; and U.S. Pat. No. 4,699,384 is a training device comprising a base which has two rods disposed at an angle to each other, with one rod forming an arc segment and the other being straight. A guide includes an obliquely upwardly extending barrier rail mounted on the arcuate rod which delineates the path of the upstroke of the golf swing. U.S. Pat. No. 3,246,898 is a swing trainer which does not employ clubs, wherein a rectangular plate is driven through a slot as a means of guiding the swing.